The present disclosure relates generally to information handling systems, and more particularly to regulating voltages of a power source commonly used to provide power to information handling system components such as servers, desktop and notebook computers, storage systems, personal digital assistants, cellular phones and gaming consoles.
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Typically, information handling systems are powered by a power supply system, which include an alternating current (AC) to direct current (DC) adaptor. The AC/DC adaptor receives an AC input and generates a DC output. The DC output is used to provide power to the information handling system components such as a processor, memory, and rechargeable batteries. Since each of the system components may have unique voltage and power requirements, a conversion of the DC output is often required. Thus, the power supply system may also include a DCDC converter for converting the DC output voltage level to multiple predefined lower is DC voltage levels typically required by various components and/or sub-systems, including the processor.
Use of a voltage regulator module (VRM) in a DC-DC converter to deliver specified lower voltage levels is well known. The VRM may take many forms including a “buck converter”. The buck converter typically “chops” the DC input voltage to a square wave of a defined frequency. The square wave has an average voltage equal to the required output voltage. A filter component typically filters the square wave to remove the alternating component, leaving the desired lower voltage. The frequency of operation of the buck converter is referred to as the “switching frequency”. A controller portion of the VRM responds to changes in load impedance, which may cause a disturbance in the output voltage unless corrected. A majority of the traditional VRM's used in portable devices are based on a fixed switching frequency, usually 300 kHz.
Power consumed by the processors is increasing from one technology generation to the next. The supply voltage required by the processors is also decreasing and is anticipated to fall below 1 Volt. The combination of lower voltages and higher currents make voltage regulation a more challenging task. In a technical paper entitled, “Investigation of Candidate VRM Topologies for Future Microprocessors”, IEEE Transactions on Power Electronics, November 2000, pages 1172-1182, Xunwei Zhou et al., and incorporated herein by reference, the paper describes a VRM topology for controlling supply voltages required by future processors.
In general terms, it is desirable for the VRM to have a high efficiency, a good transient response to changes in the load impedance and small voltage ripples. According to the above referenced technical paper, the power supply voltage ripples may be reduced by increasing the switching frequency of the field effect transistor (FET) switches used in the VRM to create the square waveform. FIG. 1 illustrates a graph of efficiency 110 versus load 120 for a low 130, medium 140 and a high 150 switching frequency of a VRM. As shown in the graph, by increasing the VRM switching frequency from the low 130 (300 kHz) to the medium 140 (1 MHz) to the high 150 (10 MHz) frequency, the corresponding efficiency reduces from approximately 80% to 73% to 40% respectively. The reduction in efficiency caused by a higher switching frequency reduces battery life and/or increases heating and power consumption.
Therefore, a need exists to develop techniques for improving the efficiency of the VRM used to provide energy to information handling system components. More specifically, a need exist to develop tools and techniques for improving the efficiency of the VRM used in a portable device that is more flexible and dynamic than such systems and methods heretofore available. Accordingly, it would be desirable to provide tools and techniques for improving the efficiency of the power conversion devices included in an information handling system absent the disadvantages found in the prior methods discussed above.